Photographic developers containing diamino-propanol tetracetic acid



Patented Oct. 20, 1953 UNITED PATENT OFFICE RichardW'. Henmand Douglas E. Piper; R'oclreste1=, N.-Y., assigncrs to Eastman-Kodak Company: Rochester; N. Y., a corporation of New-- Jersey nonmwin l Application February 12, 1952, SeriaIJNo. 271,284 I This invention relates to developers containing therein diaminopropanol' tetracetic acidas an on the quality of photographic'filinsprocessed therewith; The-prevention of these precipitates has previously received some attention; and" this difilculty 'ofthe presence of calcium in'developer solutions has been-iovercome to some extent by the use of compounds which hold the calcium inthe form'of-un-ionized complexes; Compounds which are especially characterized .bythis: property, such as. alkali hexametaphosphates and alkali tetraphosphates, have: been used; in: developing solutions to reduce thetformatiomofj the calcium sulfite scum on :thefilms; and precipitation' of calcium *in the developer. However; when these'ph'osphates stand. aqueousisolution. they gradually hydrolyze. to. the orthophosphates. which: notonly possess no; properties inhibiting calcium precipitation, butmay precipitate the calcium in the form of-calcium phosphate. Also, if orthophosphate is carried over: to the alum fixing bath, there is the possibility of the-precipitation of aluminum phosphate thereby.

Some oxygen acids, such as citric, tartaric, gluconic, etc., have proved useful as calcium sequestering agents in photographicdeveloping solutions, but usually these acids'are so' weak that, in most instances, it is desirable to supplement their effect by also adding polyphosphates. Also, the use of amino polyacetic acids, such as ethylenediamine tetracetic acid and" nitrolotri acetic acid in developing solutions, has previously been disclosed, but these compounds, although stable and effective, possess theundesirable property'of catalyzing oxidation of'the-developer by the air in the presence of traces 'of'iron'in the developer solution. For example, a developer containing'0.5%' of'one of these materials, together .ewith 8 p; p. m. of iron and-.2 p. p. m. of'copper, will cause very rapid oxidation of the developer when air is bubbled'through the solutionfor 2 hours.

One objectof our invention is: to provide a developer composition which contains: a. calcium" the formation of" calcium-containing sludges, scums, and scales in the developer-solution. A still further object of our, invention is to inhibit any local desensitization of the emulsion when immersed-in'the developer solution. Other objects of our invention will appear herein.

We have-found thatthe objects of our in-'- vention maybe accomplished by the addition of 1,3-diamino-2-propanol tetracetic acid to a developer composition in an amount constituting at least /2% of the solids in thecomposition. The diaminopropanol'. tetracetic acid may be added either to the developer composition in dry form or it may beincornoratedinthe aqueous solution of the developer. preferably prior to contacting the photographicmaterials with the developer solutions. We have found that the presence of the diaminopropanol tetracetiea'cidin the developer solution not only, prevents the formation of any calcium precipitate therein, but in addition, in the caseof"certain photographic papers, a type of local" desensitization thereof, known as freaking? is prevented; Freaking involves the failure of'an exposed emulsion to develop at the edges of areas which have been spotted with developer prior to complete wetting of the emulsion layer, as, for.-example;,by splashing; Thisphe nomenon is avoided completely whendiaminopropanol tetracetic acid is-present, particularly in concentrations of atleast 6-to, 10 grams thereof per liter of the developer.

The diaminopropanol tetracetic acid may be added to any of the. commonly employed developers, either those types'which contain borate salts, aszthe-alkaline material; or' those which contain a. carbonate,- as: the; alkaline material. Typical developers in which; diamino :p-ropanol tetracetic acid can be incorporated are the following:

, Grams Monomethyl p aminophenolsulfate 2%.; Hydroquinone 2 Sodium sulfite, desiccated; 30 Sodium metaborate' (octahydrate) 10 Potassium bromide. Water-tob'ring to 1 liter.

Grams Monomethyl-p-aminophenol sulfate 3.1 Hydroquinone l2 Sodiumsulfite, desiccated 45 Sodium carbonate, desiccated 67.5 Potassiumbromide 1.9 Water to bring to-l liter.

Inthezabove compositions, the diaminopropanol tetracetic: acid: may be; employed: in; an amount of: at least: of the. total solidcontent, and preferablyzimasproportion of 2500. 10% therein-.:. It is; apparent;- thair. amount of: calcium see 3 questering agent which is needed will depend to a large extent upon the amount of calcium which will be present in the developing solution. This being the case, the proportion of diaminopropanol tetracetic acid which is employed will be within the judgment of the individual operator. The following example, however, illustrates a satisfactory relationship between the proportion of the diaminopropanol tetracetic acid and the-calcium which is present.

Example 1 A developer containing monomethyl-p-aminophenol sulfate and hydroquinone developing agents and which was 0.5 molar with respect to sodium sulfite, and 0.07 molar with respect to sodium metaborate, and possessed a pH of about 9.8, was found to' precipitate densely with the addition of only 0.25 grams of calcium chloride per liter. However, it was found that when the following quantities of diaminopropanol tetracetic acid were added per liter, the amounts of calcium chloride designated could be added without any precipitation:

ggz g g i Grairs of Calp p cium Chloride tcrracetlc Acid r Liter per Liter De Example 2 Similar amounts of diaminopropanol tetracetic acid were added to the following developer, and similar amounts of calcium chloride per liter were added. It was found that no precipitation Water to make 1 liter.

Example 3 To illustrate the advantage of diaminopropanol tetracetic acid as regards promotion of oxidation of developer, 3 variations were employed as follows:

1. The developer formula of Example 1 with no sequestering agent added.

2. Diaminopropanol tetraectic acid wasadded.

3. Ethylene diamine tetracetic acid was added. Also incorporated in each were p. p. m. of iron.

The three solutions were allowed to stand exposed to the air for 48 hours. Solutions 1 and 2 were found to remain relatively colorless and photographically active, while solution 3 was found to have oxidized to a deep brown color and was photographically inert.

Example 4 Two grams per liter of diamino propanol tetracetic acid were added to a developer as spec-v out on this developer using the equivalent of 600 eight by ten inch sheets of photographic film per gallon of starting developer. 1.8 gallons of the replenisher were used to maintain the volume constant duringthe test. No appreciable precipitation occurred, and after a little deposit containing gelatin, silver, etc., had been filtered off, the remaining solution stayed clear and free of further deposit through the incubation and storage tests lasting 30 days. The film which had been processed in the solution was found to be free of any deposit thereon. A control test using the same materials and carried out in like manner, but without the addition of the diaminopropanol tetracetic acid, yielded a copious precipitate of calcium compounds and, even .after filtering the solution, a further deposit formed during the incubation and storage tests. Our invention is characterized by the sequestering of not only calcium, but magnesium or any other hard water cations which may be present in a developer solution. In using the diaminopropanol tetracetic acid in developer, it was found that the average sequestering value thereof was 550 millimoles of calcium per mole of the diaminopropanol tetracetic acid, and theaction of this sequestering agent appeared to be substantially independent of the composition of the developer. Therefore, in order to obtain a complete sequestering eifect, it is desirable to use the diaminopropanol tetracetic acid in an amount at least corresponding to this value.

Ezrample '5 A further illustration of the advantages of the diaminopropanol tetracetic acid over other amino sequestering agents was obtained by adding 5 p. p. m. of iron to the developer of Example 2, dividing this, and modifying the separate portions by adding 4 grams per liter of (a) diaminopropanol tetracetic acid (DPT) or (b) ethylenediamine tetracetic acid (EDT) together with sufficient sodium hydroxide to neutralize the acid. Oxidation was produced by rapidly bubbling finely dispersed air through the solutions. The developer containing the EDT discolored rapidly, being quite brown in 1 hour and dark in 2 hours and without developing activity. The developer containing the DPT, on the other hand, discolored very little in 8 hours and lost no developing activity. Nitrolo triacetic acid and methylaminodiacetic acid have been found, like the ethylenediamine tetracetic acid, to also promote developer oxidation.

It is to be understood that, if desired, the incorporation of the diamino propanol tetracetic acid in the developer may be accomplished by adding that material to emulsion compositions, and, as a result of treating those emulsions with developer solution, the diamino propanol tetracetic acid will be thereby introduced into the photographic developer composition. Another means by which the diaminopropanol tetracetic acid may be incorporated in the developer is 'byincorporating it in coatings which may have been applied to the photographic film in its preparation. Upon processing, the diaminopropanol tetracetic acid will be extracted from this coating or coatings by the developer solution.

We claim:

1. A photographic developer composition comprising a silver halide developing agent and 1,3-diamino-2-propanol tetracetic acid.

2. An aqueous photographic developing solution comprising a solution of a silver halide developing agent and 1,3-amino-2-propanol tetracetic acid in water.

3. A photographic developer in dry form comprising a silver halide developing agent and 1,3- diamino-z-propanol tetracetic acid.

4. A photographic developing solution comprising an aqueous solution of a silver halide developing agent and 6-10 grams per liter of solution of 1,3-diamino-2-propano1 tetracetic acid.

RICHARD W. HENN. DOUGLAS E. PIPER.

6 References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Ulrich et a1 Aug. 1, 1939 Bersworth Sept. 17, 1946 Bersworth Mar. 13, 1951 

1. A PHOTOGRAPHIC DEVELOPER COMPOSITION COMPRISING A SILVER HALIDE DEVELOPING AGENT AND 1,3-DIAMINO-2-PROPANOL TETRACETIC ACID. 